1. Field of the Invention
The present invention relates to a heat dissipation assembly and method of assembling the same, and more particularly to a heat dissipation assembly forming a grounding mechanism and a method for firmly attaching a heat sink to a printed circuit board and a chip.
2. Related Art
Many computer electronic devices such as chips and central processing units (CPUs) generate large amounts of heat. Excessive heat can adversely affect the stability and operation of a computer. Heat generated by a chip must be quickly removed therefrom. This is conventionally done by attaching a heat sink to the chip. Various kinds of clips, pins and adhesive tapes are used to closely attach a heat sink to a chip.
FIG. 3 shows a conventional heat dissipation assembly for attaching a heat sink 300 to a chip 500 which is mounted on a printed circuit board (PCB) 400. A heat sink 300 is attached to the chip 500 using pins 100 and springs 200. But retaining force exerted by the springs 200 is generally insufficient to firmly secure the heat sink 300 to the chip 500. This reduces the efficiency of heat removal.
In some systems, heat-conductive adhesive tape is used between a heat sink and a chip. But such tape is prone to age and lose stickiness. Thus the connection between the heat sink and the chip often becomes loose.
Furthermore, with the development of high-speed chips, generation of electromagnetic interference (EMI) is becoming an increasingly serious problem. Conventional heat dissipation assemblies do not address this problem.
Thus an improved heat dissipation assembly and a method of assembling the same which overcome the problems of the related art are desired.
Accordingly, an object of the present invention is to provide a method for firmly attaching a heat sink to a printed circuit board (PCB) and a chip.
Another object of the present invention is to provide a heat dissipation assembly having a grounding mechanism for reducing electromagnetic interference (EMI).
To achieve the above objects, a heat dissipation assembly in accordance with the present invention comprises a PCB, a chip and a heat sink. The PCB comprises a grounding circuit, and four through apertures in the grounding circuit. The chip is mounted on the PCB, and is surrounded by the through apertures. The heat sink has four metal columns depending from a bottom surface of a base thereof, the columns corresponding to the four through apertures. A method of assembling the heat dissipation assembly includes the steps of: mounting a chip on a PCB; inserting metal columns of a heat sink into corresponding through apertures of the PCB; and welding the metal columns in the through apertures so that the heat sink is in intimate thermal contact with an upper surface of the chip.